Load compensating fluid pressure brake apparatus



Sept. 20, 1949, E. s. COOK ET AL 2,482,246

LOAD COMPENSATING FLUID PRESSURE BRAKE APPARATUS Filed March 20, 1947 e a g E a 0 Q @Q a m w QEK mw w w M \L v E sT 3 N3 on em v @E 6* E 3 N m m n w r h 5 g E mm o. E 02 g 03 \mL W/ GJ m3 6* v 7/ @Q m R n m3 3 Q. 3 m 95 m On Q0 MHQ km @E @Q N@ mm mm Patented Sept. 20, 1949 LOAD COMPENSATING FLUID PRESSURE BRAKE APPARATUS Earle S. Cook, Forest Hills, Glenn T. McClure, McKeesport, and John W. Bush, Wilkinsburg, Pa., assignors to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application March 20, 1947, Serial No. 736,010

19 Claims.

This invention relates to variable load brake equipment and more particularly to the type adapted to be automatically adjusted to vary the degree of braking of a vehicle in accordance with the loaded condition thereof.

The present trend toward the use of lightweight materials in the construction of railway freight cars has resulted in much higher ratios of gross to tare weight than ever before encountered. A brake designed to provide desired deceleration and stopping of an empty car of this type is therefore wholly inadequate for the car when loaded, and conversely, a brake designed to provide desired deceleration and stopping of the loaded car could not be tolerated l on the empty car since it might result in excessive and damaging train shock and cause undesired sliding of the car wheels.

The principal object of the invention is therefore the provision of an improved variable load brake equipment adapted to automatically vary the degree of braking of a car in accordance with the loaded condition thereof.

According to this object we employ a single brake cylinder device for braking the car, the piston therein having the usual pressure chamber at the front side thereof and a second pressure chamber at the opposite side. The wellknown AB valve is used for varying the pressure of fluid in the usual pressure chamber at the front of the brake cylinder piston, and a novel relay valve device automatically adjustable according to the empty or loaded condition of the car, is arranged to operate upon supply of fluid under pressure to the usual pressure chamber to vary pressure of fluid in the second chamber, from atmospheric pressure for a fully loaded car, inversely in proportion to the degree of the load, for thereby varying the effect of the pressure of fluid on the front of the piston to-apply the brake, as a result of which, the degree of braking of the car will be varied in proportion to the degree of load carried thereby. In other words, when the car is fully loaded the pressure in the second chamber will be atmospheric pressure so that the degree of brake application of the car will be governed solely by the pressure of fluid in the pressure chamber at the front of the brake cylinder piston, in the usual manner. When the car is less than fully loaded the degree of braking will be governed by the differential in pressures acting on opposite'sides of the brake cylinder piston, and this differential will be of a minimum degree when the car is empty and will be increased in proportion to the degree'of load on the car until it disappears on the fully loaded car.

Other objects and advantages will become apparent from the following more detailed description of the invention.

In the accompanying drawing; Fig. 1 is a diagrammatic view, partly in outline and partly in section, of a variable load brake equipment embodying the invention; and Figs. 2 and 3 are, respectively, sectional views taken on lines 2--2 and 3-3 in Fig. 1.

Description As shown in the drawing, the variable load brake equipment comprises a brake controlling valve device I to which is connected the usual brake pipe 2, auxiliary reservoir 3, emergency reservoir 4 and brake cylinder pressure retaining valve device 5, as well as a brake cylinder device 6. The equipment further comprises a load reservoir I, a load compensating or variable leverage relay valve device 8 and a weighing gear or adjusting mechanism 9 associated with said compensating device. The auxiliary, emergency and load reservoirs are preferably provided in a common casing separated by dividing walls as shown in the drawing. All of the above enumerated structure is adapted to be carried by a sprung part of the car such as by the bottom of the floor thereof.

A The brake controlling valve device i may be of substantially the same construction and have the same operating characteristics as the AB valve device fully described in the patent to Clyde C. Farmer, No. 2,031,213, issued Feb. 18, 1936, in view of which it is not deemed necessary to show and describe this device in detail. Briefly however, the brake controlling valve device l comprises a service portion IEI adapted to operate upon both a service and an emergency reduction in pressure of fluid in the brake pipe 2 for supplying fluid under pressure from the auxiliary reservoir 3 to a brake cylinder pipe H and thence to the brake cylinder device 5 for, upon a service reduction in brake pipe pressure, effecting a service application of brakes on the car. The brake controlling valve device i also comprises an emergency portion l2 which is adapted to operate only upon an emergency reduction of pressure of fluid in brake pipe 2 for supplying fluid under pressure from the emergency reservoir 4 to pipe I l and thence to brake cylinder 6, wherein such pressure, in addition to that provided from the auxiliary reservoir it by operation of the service portion [0, is adapted E2 of the brake controlling valve device a are mounted on .opposite faces of :a pipeibra'cket 5 to which all pipe connections to saidvalve device are made, as shown in the drawing.

The brake cylinder device 6 comprises a hollowcup shaped casing M to theopencend of 4 V 43 is one end of a stem 44. The opposite end of stem 44 is in the form of a follower 45 which is secured to the side of diaphragm 32 opposite chamber 36 by means of a nut 46 contained in said =c'hamberand between which'rnnt and diaphsa gm iS' 'inte-rpOsed as-pring seat-41 The nut as has an extension as slidably mountsad in a bore in the casing and separating cham- Jaer36 iroma chamber 49 which isin communicais secured an annular pressure head 5 21mm 110 tionwiththe passage 38. Aprecompressed spring which projects a hollow-cup shaped non-pressure head l6. A brake cylinderpist'on t1 is slidably mounted in the casing M a'ndntonesidethbreof is the usual or a main pressure chamber -l8'to which is connected the pipe H; "The'b'rake cy1 inder piston comprises a piston head l9 to one face of which is connected aiflexiblepackingscup for preventing leakage of fluid under pressure from the pressure chamber I 8 to the opposite-side of the piston. Secured to and projecting from 2:

the pis'ton H in a direction away from the pres-- sure chamber I8 is a hollow stem 2| the oppos'i-te end of which is slidably mounted in a ring 2-2 secured in the pressure head 15. Carried "by the pressure head I5 and ring 22 is "a packing cup 2.;

or ring .2 3 having sealing and sliding contact with the outer peripheral surface of the stem- '2'! -for preventing leakage of fluid under pressure 7 from a compensa'ting pressure chamber zlformed around said 'stem between the pressurehead i5 and the piston H, to a non-pressure chamber 25 formed within said stem and open to the 7 interior of the non-pressure head 56 and thence to atmosphere through a port 26 in said non-pressure 'head. The chamber 245s open to a, pipe 27 through which fluid under pressure is adapted to be supplied to and released from said chamber by operation or thecompensating valve device 8, in a manner which will be hereinafter described.

The piston head l9 -is-provided 'witha hollowboss 28 projecting into *the hollow stem 21 in coaxial relation to said head and stem, and one end of a hollow rod 2% is secured in said boss. The rod 2 9 extends through the non-pressure chamber 25 and a bore provided in 'theouter end 01 the n'on-pressure'head 1 (its the-exteriorthere- V of, said rod being hollow to accommodate the usual push rod (not shown) for connecting the piston head H to the brake rigging (nots'howh) 'of the car, in the conventional manner. Encircling the "hollow rod '23 is a brake cylinder piston release spring '39 one end of which bears against the piston head 1'9 for moving the brake cylinder piston I! to its brake release-position, in 5? which it is shown in the drawing. 'The opposite end of the release spring -39 is supported'on the non-pressure head [6. i

The-load compensating device 8 comprises pilot and balancing flexible diaphragms 31 and 31h re- {39 spectively, preferably of thelsame areaarranged :edge to edge in spaced relation and with their axes parallel. At one side of diaphragm 3}! is .a pressure chamber '33 which is connected to the brake cylinder pipe I'I through a passage stand 65 -:a pipe 35; 'At the same side of diaphragm 32 is :a balancing chamber '35 which is connected "to pipe '27, leading to pressure chamber 124 in the brake cylinder device, by way of a choke or restricted passage 31 and a passage, Engaging J70 the opposite face of diaphragm 31 is 'a follower 39 provided on one :end of a stem 4'l3 "the opposite end of which engages an equalizing member "or beam 4| within a pocket '42. Engaging the opposite end of the beam 4 within a similar pocket 75 contained in chamber 35 has one end supported :by-the casin g while its opposite end bears =against-the spring seat 41. The nut 46 and ex *ten'sion'i48 thereof'are provided with an axial bore *51 'openlat oneiend'-to a chamber 52 in the casing and provided around the opposite end with a wafivsiseat arranged for engagement by a release valve 53 which is contained in chamber 49 and whichhas a fluted stem 54 slidably mounted in said bore. 7 Chamber52is in constant communication with atmosphere through apassage 55. It f'll be noted that the diaphragmstems "4t, 44 an'd'beam "41 are contained in chamber that the lower faces. of the two diaphragmsiLS I and 3'2 are both'sifofi-ect toatm'ospheric pressure in said chamber. 7 V 1 7 The release valve 5-3, opposite the fluted :stem '54, has an enlarged annular collar 55"one side of which is provided'f'or contact'wi'th'arcfoir'ibined valve guide and "stop ei'ein'erit 5'! projecting" rom the easing into chamber 49., Wh le the opposite side is arranged for 'co'ntact'by the, end o'fa fluted stem 58 of a coaxially arranged fluid pressure which is carried :by n ale as. on an enlarged central portion 456 .t'hereofftli'ign 2). Ilhe iaxle has itedi ced .end portions :61 at opposite ends end portions are rollers one :disposed:at either side of the beam 41 and-arrangedto roll 011 a; fiat surtace =6 9 inthe casing. The "surface :65: is :tormed at right'rangles to the normal, parallel .axes .of-the=diaphragms 3;! and 32. r

The equalizing member or -beam 4| is held against longitudinal movement bya :yoke 70. pivoted-at one end on'a pin 'l carried 'in arms .12 projecting from the casing. The two arms of the yoke 74) are disposed at oppositesides of the of the centralportion 56 and mounted'' n these beam 4| between the rollers 68, and their ends are pivotally connected to said "beam'inear its 'center by a pin 'The roller 64 is adapted'to :be adjusted relative to the beam]! longitudinally thereof =to provide at its line of contact with'the beam at fulcrum therefor, :Zthe yoke 11) being eifective during such :adiustment, "and at :all other times, to prevent longitudinal 'movementiof said *beam'ibut 'in 'no' way j interfering with rocking movement of "the dream about its fulcrum connectron with :the roller-"64, whih'will be later described. v 7 a Disposed between the equalizing member or beam and the surface 'B'Qand extending len th wise of' and =subs'taritiallyparallel to said surface is a piston 'rod' 'l-fi. The rodflhas asubsffiantiallt send-circular recess 15' of larger radius than roller 64 for receiving said roller, and at either side of said recess said rod is provided with a transverse slot I6 open to the top edge of said rod and in these slots the enlarged central portion 66 of axle 65, at either side of the roller 64, is slidably mounted, the rollers 68 being disposed at opposite sides of the piston rod I4.

Connected to one end of the piston rod I4 is a bias piston 11 open at one side to a control or pressure chamber I8, While the opposite side of said piston is open to the atmospheric chamber 52. A shoulder I9 in the casing is arranged for contact by piston H for limiting movement thereof in the direction of the left hand, movement in the direction of the right hand being limited by contact with the casing. The piston rod I4 projects from the piston 'II through the chamber 52 and a bore in a wall 80 separating said chamber from a chamber 8| in the casing, the end of said rod opposite said piston being supported by contact with the wall of said bore. An adjusting screw 82 is secured in the end of rod 14 disposed in chamber 8|.

The fulcrum roller 64 has two extreme positions with respect to the equalizing member or beam 4!, one position being that in which it is shown in the drawing and which is defined by contact between piston 11 and shoulder 79, and which position will hereinafter be referred to as the empty position which said roller will occupy when the car is empty. In the other extreme position to be hereinafter referred to as full-load position, the roller 64 will be substantially below the end of the diaphragm follower stem 48 and the piston 'I'I will be slightly spaced from contact with the end wall of chamber I8, and this position will be assumed when the car is fully loaded. For various degrees of car load between empty and full-load the roller 64 will assume a corresponding position between the empty and full-load positions, just mentioned. The automatic adjustment of fulcrum roller 64 to its different positions will be hereinafter described.

The piston rod I4 is provided with a plurality of teeth 83 along the side opposite the beam 4| for engagement by teeth on one end of a latch or looking plunger 84 which is mounted to slide in the casing in a direction at right angles to the length of said rod. A lever 85 fulcrumed on a pin 86 carried by a projection of the casing has one end connected to the plunger 84. The opposite end of lever 85 is connected to one end of a rod 81 by a pin 88, the opposite end of which rod is in the form of a follower 89 which engages one side of a latch or plunger control flexible diaphragm 90 which is clamped around its periphcry in the casing. A spring 9| encircling the rod 81 and supported at one end on the casing bears against the diaphragm 99 for urging it and plunger 84 to the position in which they are shown in the drawing, in which position said plunger is in locking engagement with the piston rod I4. At the opposite side of diaphragm 9| is a pressure chamber 92 to which fluid under pressure is 7 adapted to be supplied for deflecting said diaphragm against spring M for thereby actuating lever 85 to draw plunger 84 out of locking engagement with piston rod I4.

A check valve 93 contained in a chamber 9c is provided for closing communication between said chamber and a chamber 95 into which extends a projection 96 of the plunger 84. With plunger 84 in locking engagement with piston rod 14 the end of projection 95 is spaced from check valve 93 a distance slightly exceeding the extent of movement of said plunger required to release said plunger from said rod. Upon further movement, the projection 96 is adapted to engage and unseat valve 93. A spring 91 contained in chamber 94 acts on check valve 93 for urging it to its seat. A ring seal 98 on plunger prevents leakage of fluid under pressure from chamber to chamber 52.

Spaced from and extending generally parallel to the bias piston 11 and its rod 14 is an adjusting piston 99 and a rod I08 projecting from one side of said adjusting piston through a non-pressure chamber IIJI which is open to chamber 52. At the opposite side of piston 99 is a pressure chamber I62 open to the bias piston pressure chamber I8 and to a passage I03 which passage also connects to chamber 95. A spring I04 contained in the non-pressure chamber IIJI and encircling the rod I00 is supported at one end on the casing,

\ while its opposite end bears against piston 99 for urging said piston and rod to the position in which they are shown in the drawing. The end of rod I00 opposite the piston 99 is supported in a bore in a Wall I95 separating chamber 52 from a chamber I66.

A lever it! extending through an opening I08 in a horizontal portion ofthe casing wall 80 is fulcrumed therein on a pin I995 The end of this lever in chamber 8| is arranged for'contact with the end of the adjusting screw 82, while the opposite end of said lever is disposed in a slot III) provided in the adjusting piston rod I60. The slot H9 is of such length as to permit the lever I9! to be free on pin I09 with the adjusting piston 99 in the normal position in which it is shown in the drawing, and to'permit a chosen extent of movement of said piston against spring I94 before an end wall Ill of said slot engages said lever.

In chamber I66 the end of the adjusting piston rod I06 engages a roller II 2 provided in the end of an arm I I3 of a bell crank like lever Ild which at its knee is fulcrumed on a pin II5 secured in the casing. The lever H4 has another arm H6 on the end of which is provided a fixed cam surface II'I arranged for contact by a roller H8 provided in one end of a lever H9 the opposite end of which is secured to turn with a shaft I26 journaled in the casing. The cam surface II! is of least radius at the end adjacent the roller IE8, as viewed in the'drawing. Pivoted by a pin I2I to the bell crank arm II6, adjacent the opposite end of cam surface H1, is an adjustable cam element I22 having a cam surface I23 constituting an extension of the fixed cam surface Ill. The cam element I22 is supported on one end of an adjusting screw I24 carried by the lever arm H3. A lock nut I25 on screw I24 is provided for contact with the lever arm M3 for securing the screw in an adjusted position.

A lever I26 disposed outside of the casing has one end secured to turn with the shaft I23 while connected to its opposite end by a pin I21 is one end of a connecting rod I28. The other end of rod I28 is connected by a pin I29 to one end of an arm I38 the opposite end of which is mounted to turn on a pin I3I carried by a sprung part I32 of the car.

Also pivoted on the pin 929 is the upper end of a measuring arm I33 comprising over-lapping, upper and lower parts I34 and I35 rigidly clamped together by lock bolts I36. The lower end of the lower part I35 has an ofiset portion provided with a striking surface I31 for contacting the underside of an unsprung part I38 of the car truck in a substantially horizontal position of "passage i83- from the'biasi'aiu surfa'e. i ifieaeh side ofipi-n lemme m'ws ur'mg arm reams am ups'taniiin'g "ear max -the twwea-i'sbeingarranged' fer: engagement by m re ehd o'f a leaf' 'tnsibn s'pririg -l-'4ll' extendi rig i-parallel ==to ahd over the tep i af the arm use and secured-at itspppo'site end to 'said- -A1bias spring 1 4 I is mterpcse'dunder s-pressure between arm I30 and the sprungpart I32 for normally laiasing tlie=arm=- I 30.;iheabell icrankflike lever I M safid' the connecting:p'arfistothe positionin which they are shown'the drawingpunder' which ecn- I46 which "is pen-to atni0spherethroughvent parts 141 and+48 ahd-which 'cont'ains a spring 149'- the Oppositaends of which bear against-followers "159 and "I 5! engaging diaphragms "143 and |44,-respectively, for 'urgingsaid diaphragm apart. "At the outer face of diaphragm"! 43,which is largerthan-d-iaphrag-m |-44,=-is-'a pressure cham- --ber l52which is 'connected to a passage 153 also connected to the 1a-tch diaphragm chamber 92. At theppposite face of-"diaphrag'm' M4 "isra valve chamber "I54; which is? in -constant comr'nuhieation with the-brake pipe 2 through a passage 1 55, "a choke I56, a-passage l Shand thence by *way of a pipe l58-inwhich there is provided; a choke I 59. ;-In---a'ctual practice thepipe I58 isconnected directly to pipe bracketl 3 of theAB-vahre device I} and through said pipe bracket to the 'Well known brake pipe connection (not-shown) therein, and "the choke l59 -is disposed' in said bracket' but forthepurpcse of simplicity in the'present application, the pipe"! Ems-shown in the drawing conneicteddirectly-to the brake'pipe Z as-al QOVe described.

'j'lhe 'cut-oijvalvedevice +42 further comprises a slide valve IBU-cemta'ined' inchamber means mounted therein -between- -s-pa'ce-shoulders "Nil formed -ona-stemWfiZ. -Gne-end of the "stem 1 52 is connected -by -follcwerl5l and a cap screw $63 130 the center 'of 'diaph-ragm- 1 44'-for rendering the slide valve 466 movable -by' -and with said diaphragm. v

fGcnn-ectedto the seat of the 'cutoff'slide'valve N58 is a-' -passage lii l which leads toatmbsphere, V and'-=adjusting*pi'ston chambers TS'a-nd H22, a passage lfi5 whic'hfleads fto the checkvalve ohamber-94=-and toa' timing g'eservoin I36, and'passage 1 53 which leads to the" l'atch'diaphragm chamber 92' -and*""to-diaphragm cha-mber l 52 he slide'valve 160 is "provided with ports l B1,"'f|63,""|'59'2,nd"-l 1-0 and a choke connection 1 H between portsd-G'F-and 1168- for a purpose to" be: hereinafter described.

r The load 7 eompensatir g device 8:--f-urther-" Tcomprises two check valves l-l2 -and HS a-rranged-in V series ina connection between passage l51- and V I Yr -a"pa s'sa e I74, and a bias'spring I acting on 275 the same timesfluid .will 'alsdflows fromsehamber occupy f'the cut ln" the cheek walve if far lurging -it ato iits' eeat. Ihe -passage I s cdnr'i ectedthrhug'h assholes PM to aipassage fl 'l'] wtmeh rleads to passag tl connectd' to the' siipfily valve iih aimber fifl and toipe-:62 leading eto' theiload reservir =11, r a

' Dperiitibn v in j operaticnplet' it' he initially :iassuniedwthat the-brake equipment is-void of=-fluid underi'pres sure and that condition rthe =requipment aim -0 peraticn-fiuid under pressure -is suppl-ied tdxthe brake pipelrinthe psuahmlanner.

The brakecontrolling valve -dev-icel Willirespond, in themsual: manner, towthe i pressure of fluid: thus -supplied' to the brake-pipe :2 to 'charge the =au xiliary rese rvoir 3 :and tlae emergency reservoir-4 With-fluidunderipressure' from' said brake -pipe, sand toat the same :tirn'ewpen to atmosphera if not-a111eadyiopenfitheflbrake :cylinder pipe; H and thereby the g pressure chamber T8 in the braka-cylindcr devicer 6. --l/Vithipi-pe-- H thus open to atmosphere the pilotediapih-ragm chamber 33 in the load-compensatingidevicew will also -het ope-n+to atmosphere by way of;ip'assage lands-pipes and -ll,+whichwillper m-it spring SlB to deflect the loalemeii-ig diaphragm 32 a ainst its stem-- li and roek-heam aboutuits fulcrum coanectiqn- -wit-h .rol-ler filL-regardless-of the adjusted position 'ef saidyroller, to deflect the pilot Qdiaphragrm 3] ime e onta-ctawith the casing, in Whichpositiqn thesaparts are -t-sh0wn onthe'drawing. w v V a With i the halancing diaphragm 32-;V'p0si-ti-oned as Tjust described; sprir-1g -B3;wil1oseat the: fluid pressure supply va1ve 5J9 and r the-:- coll-ar: 56eon the release valve v53 .uiill =lJe-.-just out. of"' Contact 'wnmhe supply valve stem;iiii -and-inrengagement H *hold said release valve out of vcor'i tact with 1755 86313 eon the riut extension 118, With .the-i release waive :53 "thus open charfibers 2'4 in the "brake cylinder device #6,; ill beeopen to atmosphereiby way fchamber #5 2- and port 55. With both jpfessu r'e chantdoers "48 hand ';24 in'the" brake ciaifider 'qeviceis .thus p mosp ere" the" braka yiinC rJpiSt I! will: as-

s meits" brake releasemcsitich, which hit is showni f'the'drawing, under the action cf 'ithe J "IWhen fii-iidf uliderl deviceisarid u ence thrpughs passage 151, past the. check 'valve'w'n afid'j r1 3, eth rglljglh: hok ilis, passages "g 'H' ahd. s1, and pipe" 62lt0lthelk1oadreservbirrrwenmgmg "said; reservoir with fiu id dis increasedto a-chosen degree, "such. as"' for'ty 'pounds,"and'"durihgithetime requiredto csut'ain I A V fi fland-feflaandthereby the connected compensating. pressure rcham-ber' en sto -atmg ant the p'res'su reibfffiuid V V [54 through port I10 in the slide valve to passage I53 and thence to the latch diaphragm chamber 92 and also to diaphragm chamber I52.

When the pressure of fluid thus supplied to the latch diaphragm chamber 92 is increased to a degree, such as ten pounds, sufficient to overcome the opposing force of spring 9!, the diaphragm 90 will deflect against said spring and actuate lever 85 to draw the locking plunger 84 out of locking engagement with the bias piston rod 14, following which, the projection 91 of said plunger will engage and unseat check valve 93. Fluid under pressure supplied from the cut-off valve chamber I54 to the check valve chamber 94 will then flow to chamber 95 and thence through passage I03 to the adjusting piston chamber I02 and to the bias piston chamber 18. Fluid under pressure thus provided on the bias piston 11 will promptly move said piston to the position in which it is shown on the drawing, if it is not already in said position, for thereby actuating the axle 65 to move the fulcrum roller 64 to its empty position, in which it also is shown in the drawing.

When the pressure of fluid in chamber I02 acting on the adjusting piston 99 is increased to a degree sufficient to overcome the opposing force of spring I04 said piston will move against said spring and thereby rock the bell crank like lever H4 in a clockwise direction about pin H5 and through the medium of cam surface I I1 the levers H9 and I26 will be rocked in a counter-clockwise direction and pull the connecting rod I28 in an upwardly direction. This movement of the connecting rod I28 will in turn rock the arm I30 I;

about its fulcrum pin I3I and thus move the measuring arm I33 into contact with the unsprung part I38 of the truck. The measuring arm I33 as it is thus moved will first contact the side of the unsprung part I38 and will then be lifted vertically to bring the surface I31 thereof into engagement with the lowermost part of the unsprung part I38, this latter movement being relative to the arm I30 and being permitted by spring I40, and it will be noted that when surface I31 contacts the unsprung part I38 it will prevent further movement of piston 99.

When the equipment is initially installed on an empty car and is Void of fluid under pressure, under which condition the parts thereof will occupy the positions in which they are shown on the drawing, the measuring arm I33 is moved manually against the side of the unsprung truck part I38 against the tension of spring I40 and by loosening and subsequently tightening the locking bolts I30, the surface I31 on the measuring arm I 33 is spaced away from the lower most portion of the unsprung part I38 a certain chosen distance, so that when said surface engages the lower most part of the unsprung truck part I38, during initial charging of the equipment on an empty car, the end wall III of slot I I0 in the adjusting piston rod IOI will just contact the adjacent end of lever I01 with said lever in the position in which it is shown on the drawing. By adjustment of the regulating screw 82 in the bias piston rod 14 the fulcrum roller 64 can then be accurately adjusted to its empty position, corresponding to the empty condition of the car. Furthermore with the car empty and the parts adjusted as just described roller II8 carried in the end of lever I I9 will be just at the junction of the fixed cam surface I I1 on the bell crank lever H4 and the cam surface 12 0 .1 $116} adjustable element I22.

spect to the movement 7 deflection. It will thus Now assuming that the car is fully loaded the body thereof will occupy a position closer to the unsprung part I38 of the truck than when the car is empty. In this fully loaded position the surface I31 on the measuring element I33 may therefore initially occupy a position such as indicated by dot and dash line I19 in the drawing. In charging the equipment on a fully loaded car the adjusting piston 99 will therefore be moved by pressure of fluid in chamber I02 a greater distance to bring the surface I31 of the measuring arm I33 into contact with the underside of the unsprung part I 38 than is required when the car is empty, and to effect this greater movement of surface I31 the cam surface I23 of the adjustable cam element I22 will become effective against theroller I I9. When the adjusting piston 99 is thus operated to bring the measuring element I33 into contact with the underside of the unsprung truck part I38 on the loaded car, the end wall III of slot III! will contact the end of lever I01 and then rock said lever in a clockwise direction and thereby actuate the bias piston rod 14 and the bias piston 11 against pressure of fluid in chamber 18 to a position in which the piston substantially contacts the end wall of chamber 18 and in which the roller 04 is in its full load position, substantially under the end of the diaphragm follower stem 40.

For various degrees of load on the car, between empty and full-load, the car body will assume corresponding positions with respect to the unsprung part I38 of the car, and as a result, the measuring arm I33, and the fulcrum roller 64 as actuated by the adjusting piston 99, will assume corresponding positions between the empty and full-load positions, as will be clear from the above description.

On different cars the deflection of the body supporting springs vary, as for example, on one car the deflection of the springs between the empty and full-loaded conditions of the car may be only three quarters of an inch, while on other cars it may be as great as two inches. The cam I22 is adjustable by screw I24 in accordance with the deflection characteristics of different car supporting springs to provide for greater or less movement of the measuring arm I33, as required to properly position the fulcrum roller 64 in ac cordance with the particular car to which the equipment is applied. For instance, assuming that cam element I22, as shown in the drawing is adjusted for a car spring deflection of three quarters of an inch, and that the equipment is applied to a car on which the deflection of the body supporting springs is two inches, the cam element I22 will be adjusted outwardly in a clockwise direction to a position for increasing the movement of the measuring arm I33 with reof the adjusting piston 99 to a degree which will provide the same positioning of the fulcrum roller 64 with respect to the fulcrum beam 4| for the fully loaded car as would be obtained on a car having a less spring be seen that regardless of the different deflection characteristics of the body supporting springs on different cars to which the equipment is applied, the adjustment of the cam element I22 provides for obtaining the same positioning of roller 64 with respect to the fulcrum beam M for different degrees of load on the different cars.

While the fulcrum roller 64 of the load compensating device 8 is being adjusted to a pos tion correspondingsto the empty or loaded condition .l I of the oar as *just described; ;the:pressure: of luid in adiaphragm chamber I52- of the.- cut-out' valve device 'l 42 will continue ".tOllilCIEELSG' with the in? crease inpressure in the cut-off valve-chamber l:5 l-and in the brake pipe -2.. This increaseinr against-diaphragm li l. 'Ilhen whenthepressure Of 'flllid'ill brake pipe 2 and in valve chamber 154 isrinbreas ed to a degree;such-as 40 poundsrwhich V is I suflici-ent' toovercome the" opposing increased pressure-f spring- 'lell thewdiaphragm HM'ewilL-be deflected toward the right hand'to a position: de-

finedby-contaotbetween the followersl 51 and the spacer-el-ement -ifi for thereby shifting the slide valved 6M0 a cutoff position;

In the cut-01f pOSitioWofthe'fcut off slidewaive Hi0- the port H31- therein connectspassage I53 to the atmospheric passage L64 whereupon the fluid-under pressure -ispromptly vented from the latch diaphragmchamber :9 il and from diaphragm charnberdfiz The venting; of. fluid-under pressure-from: the latter chamber permits the diaphragm 'M3 to -bereturned *tothe position in which it is shown in the' drawing by spring" 149; which reduces the force of said springgon the diaphragm" Mil -to a degree which will-prevent nturnof 'thelatter diaphragm and: of: the slide valve 1-89 to their cut-in posit-iomshown in the drawing, until the brake pipepressure effective invalve: chamber P54 is reduced- 'to a relatively low degree, such as 8 pounds, thereby; insuring that. the cut-out slidevalve I61 will remain in icut-oifpositiong :so-as to -maintain the f ulcrum roller-64- in :itsadjusted=position; during all'roperatiOIiDf the brakes on: thevGa-I while connected in atrain. 7 7 r r The" venting of fluidwunder pressure from' the latch Vidiaphra'gnichamber 412- permits spring. or. t'o return diaphragm ile-and lever 85=toit-he DQSi-r tion in which they are shown :on: thedrawing;

This operation of lever -85 actuates plunger 84 out of engagementwith the check valve 93a and into lockingengagement with-thebias-.piston-rod M; The check val-ve 83: will then be seated by spring '91.

At the same time'a's the fluid" under pressure is released from the latch diaphragm chamber Shana from' diaphragm chamber 152,1 port I68 in the cut-off slide valve [66 connects-passages I65 and I63" to the atmospheric passage. 16th?! way of the choke connection Hi. Thetiming reservoir l fifiprevi-ously charged-with fluid-under pressure from'the brake pipe; isthusl placed in communication with the adjusting piston cham b'er I02 and bias piston chamber 118,. and said reservoir and these chambers are all opened to atmosphere through thelrestricte'd connection l-T l", whereby the pressureof ifluid in said reservo'ir and chambers will be gradually" reduced at a rate determined by the flow capacity of said connections r The volume of the timing reservoir lfiG with i 1 z csaga e respect to theyfiOW capacity of the chokexcon' v nection 1H is such as to maintain sufficient pres:

sureon the bias piston Tl and adjusting pistonvtfl to hold thebias piston rod 'i-lagainstieverle'l ahd to hold the measuring arm 13 3 in contactzw-ith the unsprung part; I33 of the truck :until; after plunger' 85 is moved into lockingengagementwith 7 the bias piston 'rodl' i, following which,.ithetpres.=- sure of fluid inas-aid reservoir and chambers: will continue to reduce:- to atmospheric pressure: Whenithe pressure of fluid in :thei'adjusting chamber 162 is thus sufficientlysreduced; spring I534 will return the adjusting piston 89 120: the

position inwhi'ch it is shown in the drawing; but 7 the bias piston-77, and-therebythe fulcrum roller- Gfi; will bem'aintained inthe position to which they were adjusted by the locking actionL of plunger EM;- '7

When the adjustingpiston 99 is returnedito the position inlwhich itis shown on theidrawingz bias spring i i: acting on thearm liiiwill urge said arm downwardly for moving'the'measuring-1mm out :of contact with the unsprungtipart I38 of the truck and backto the pcsiti'ont in: which it is snowmen the drawing; and: duiiin'gr such movement-- the connecting; rod? 12K. ian'dfithere'by levers ins and lit-s will also-he:actuatewbysaid spring t'o-return the bellf-orank like lever "H4 to.--the =p osition :in which it alsoris shown? on -the drawing. With" the measuring: element". I33

' moved downwardly and to onessidei-o'fi' the un' sprung parti 38 of the truck; contact therebe; tween is positively avoided 'during:operation: of the car in -.the train-aroun'd curves;- "over' humps; etc, to prevent'damage to these parts-a, After ther cut-out valve devices: 1:82Hoprates to cause lociringeor the-fulcrum" roller 64in its aid justed: position 'andrdisengaeement of: thermeasrtiring-arm i tawfrom-the unspnung: truckpart 138; as? just described; the brake piper?willicontinue te be increasedzup to thernorrnal pressure carried and'thewload Y reservoir '7 will become-charged: by wayofithe-check valves +12 and lilfsz'to substantially: the same-degree of pressure. as "will" be apparent; In the-operation above describedgthe load reservoir charging chokez" H6 restricts flow or fluid under pressure to the loadareservoir F'sohas to causemoreprompt operation ofithe load compeneating device d-to: adjust theposition o'ff 'the ful crumrolier-M, and therefore, more promp't conelitioni-ng; o'fthe-car forloperation in a train, than could-otherwise be obtained:v The chokes i 59and era, :acting in series; limits the rate of supply of rvoir 1:63"being connected to valve chamber 'l5'4 inthecut-in: position of the cut-o'lf valve" device i42 actslin'conj unction with the now capacity of saidzcholces'toiinsure that the cut-out valve device 7 ifirwillinotimove" out of its cut-in position, in which: it is shown in'the drawing, to its cut- 01T position for a definite period of time, even if the brakepipe' 2* on the car is connected to 'a fully cnargeu lcrake pipeo'f'a train; as might occur in service; period or time being. adequate to insure proper adjustment of the-fulcrum roller 6'4 as' ahove-de'scribed; The choke" I 59 is also effective; in case'thepipe I58 between said choke and theioad compensating device 8 becomesbrole'n' to so restrict ventingof' fluid under pressure from the brake pipe asto prevent an emergency rate of reduction in pressure in the brake pipe 2 and the connected braket pipe of a train; for thereby preventing an undesired emergency application of brakes on the train under such a condition. The choke I59 also acts in a similar manner, upon connecting the brake pipe 2, when void of fluid under pressure, to the fully charged brake pipe of a train, to prevent an emergency application of brakes on said train.

With the equipment conditioned for operation, and with the brake pipe 2 fully charged to normal pressure, if either a service or an emergency reduction in pressure in said brake pipe is effected, the brake controlling valve device I will operate to supply fluid under pressure from either the auxiliary reservoir 3, or from both the auxiliary reservoir 3 and emergency reservoir 4, respectively, to the brake cylinder pipe H and thence to the main pressure chamber l8 in the brake cylinder device 6, in the usual well-known manner. Fluid at the pressure thus provided in the brake cylinder pipe II will flow through pipe 35 and passage 34 to the pilot diaphragm chamber 33 in the load compensating device 8.

Let it be assumed that the fulcrum roller 64 is in the empty position in which it is shown on the drawing, The pressure of fluid in the pilot diaphragm chamber 33 will then deflect the diaphragm 31 downward and rock the beam 4| about the fulcrum connection with roller 64 and thereby act through stem 44 to move the diaphragm 32 and nut 46 in an upward direction into contact with the release valve 53 and then actuate said valve to open the supply valve 59. Upon opening the supply valve 59 fluid under pressure from the load reservoir 1 will flow through pipe 62, passage GI and the supply valve chamber 60 to chamber as and thence through passage 38 to the compensating pressure chamber 25 in the brake cylinder device 6, and at the same time fluid under pressure will flow from passage 38 through choke 31 to chamber 36 at the upper side of diaphragm 32. Choke 31 is merely a stabilizing choke and its purpose is to prevent the pressure in diaphragm chamber 36 increasing ahead of that in the pressure chamber 24 of the brake cylinder device 6.

Fluid under pressure will thus continue to be supplied to the compensating pressure chamber 24 in the brake cylinder device and to diaphragm chamber 36 until such pressure acting on diaphragm 32, plus the pressure of'spring 50, acting on one end of the beam 4! is increased to a degree sufficient to over-balance the pilot pressure in chamber 33 acting on diaphragm 3|, whereupon diaphragm 32 will be deflected downwardly to permit closing of the supply valve '59 by spring 63 for preventing further flow of fluid under pressure to the compensating pressure chamber 24 in the brake cylinder device 6. When the supply valve 59 is closed, as just mentioned, there will be no further flow of fluid under pressure to and consequent increase in pressure of fluid in diaphragm chamber 36 whereupon deflection of diaphragm 32 will cease in a lap position in which the fluid pressure release valve 53 is still seated. With the fulcrum roller 64 in the empty position, substantially midway between the diaphragm stems as and 44, the pressure of fluid obtained in the compensating pressure chamber 24 of the brake cylinder device 6 will therefore be limited to a degree slightly less than the pressure of fluid in the main brake cylinder pressure chamber 18 as determined mainly by the pressure of spring 50 on diaphragm 32.

The pressure of fluid thus provided in the compensating pressure chamber 24 of the brake cylinder device 6 acts over the area of the brake cylinder piston l1 outside of the hollow stem 2 I, andthe force thus created is less than that due to pressure of fluid in the main pressure chamber 18 acting over the full area of said piston, so that said piston will be forced in the direction of the right hand against the release spring 3|] to apply the brakes with a pressure equal to the differential between these forces, this latter pressure being adequate to insure desired braking of the empty car.

If the fulcrum roller 64 is in its full-load position, substantially under the end of the diaphragm stem 4|, the pressure of spring 50 on diaphragm 32 will hold said diaphragm and thereby the diaphragm 3| in the position in which they are shown in the drawing against the maximum pressure of fluid which will be provided in the brake cylinder pressure chamber l8 and thereby in the pilot diaphragm chamber 33 in effecting an application of brakes on the car. As a result, the release valve 53 will be maintained open by spring 50 so as to maintain the compensating pressure chamber 24 in the brake cylinder device 6 open to atmosphere, as a result of which, the braking force obtained on the fully loaded car will be governed by the pressure of fluid provided in chamber l8 acting over and times the full area of piston l1.

Now assume that the fulcrum roller 64 is adjusted midway between its empty and full-load positions, for example for a car half loaded, fluid will be provided in the compensating pressure chamber 24 'in the brake cylinder device 6, and thereby in diaphragm chamber 36 in the compensating device, until the pressure thereof plus that of spring 55 is able to over-balance the pressure in the pilot diaphragm chamber 33 so as to permit closing of the supply valve 59, whereby the brakes on the car will be applied by force, governed by the pressure of fluid in chamber 18 acting on the full area of piston l1 less the opposing pressure of fluid in the compensating pressure chamber 24 acting on a smaller area of said piston, which opposing pressure is proportional to the semi-loaded condition of the car, whereby the braking power delivered by the brake cylinder device 6 for braking the car will be proportional to the semi-loaded condition thereof. It will be apparent that for any other adjustment of the fulcrum roller 64 between its empty and full-load positions the pressure of fluid in the compensating pressure chamber 24 of the brake cylinder device 6 will be correspondingly limited so as to provide a braking force for the car proportional to the degree of load on the car.

In case an emergency reduction in pressure in the brake pipe 2 is effected for effecting an emergency application of brakes, the pressure in said brake pipe and thereby in the cut-off valve chamber I54 will be reduced to atmospheric pressure, and when the pressure fluid in said chamber becomes reduced to a degree below the opposing force of spring 49, said spring will actuate diaphragm M4 and the slide valve I60 back to their cut-in position, in which they are shown on the drawing. When the slide valve IE0 is returned to its cut-in position the latch diaphragm chamber 82 will be open to the valve chamber I54 and thereby to the brake pipe 2. The pressure of fluid against which spring M9 can thus return the cut-off slide valve I60 to its cut-in position is however lower (for instance eight pounds) thanv that required in the latch diaphragm chamber 92 for actuating the diaphragm 98 to move plunger 84 out of locking engagement with the bias piston e e m brake? cylinder,- device' 6;: until: after asufficientpress re. orifluid is; obtained iii-.themain pressure, chamber lsteaactuate-thez brake cylinder piston 1-1 to; pnsitiyely and promptlymflveg the brake: ShQGSpQIl-flihfiy car; intocontact-with. thez car wheels;-

foil vsin r which, pressure of; fluid inrsaid co-m.--

pensatin chamber; will increase substantially ini nison: with; that; in; thei main; pressure; chamber: li -for; limiting the degreeof braking on the; car..- in aneordancefwith: the load: carriedwthereby:

an: increasein pressure of.- fluid-imbrake DiPfi'iZiIOIi cazusingroperaition-z of the: brake control+ lin -z Valve; device to: efiect; a. release of fluid under pressure from the brake cylinder. pipe; H: nd thereby from: the. main pressure? chamber [8 11inthe:brakeecyiirrderdevice 6 forreleasing, the brakes: on: the cane corresponding reduction in 131185311128! off-=2 fluid: in pilot diaphragm chamber 3:3:1wi1i occur: the pressure of fl'uid'in chamber; 3,3.1531'111113 redncedythe. presssure of. fluid:

3i; nlius-ithe pressure: ofspring 511; will deflect: the diaphragm 32; and: thereby rock. the hamflliz aboirtiitsafiilcnnmconnection with roller Mitorpuiling the nut extension 4'85zoui1 of' engagement with the releasevalve 5.3. Upon; opening of the; release valve fluid? under. pressure-will: be neleasedafroml the compensating; pressure; chain,-v hen 2.4i in;the brake cylinder device along with thareleaseiofi fluid-,under pressurefrom the-main:- pressure chamber it: When the pressure of fluid inipressure chamber 18: of the brake cylinder device: 6: is thus: reduced sufficiently' the; brake. cyliinderrelease spring 3flrwill return-.fpiston=l:1 to its release positionshowninthedrawing; whereby the-brakes on the car willizbereleasedi Ltwillfof course be evident that when the roller Mrisin full-load position. and? no fluid pressure is-.-provided= in the: brake cylinder compensating. pressure chamb'enzlliiin: effecting an: application otfbralces; there will be no releaseof fiuid theree from in effecting a release oil brakes; but there willbeflow off fiuidf'pastlt'he open releasevalve 53 into: said: chamber as the brake cylinder piston "is returnedto its brake release position; it'beingnoted-that-the open release Valve 5'3 on a fiilly loaded carprovides in efi'ecta breathenconnection between the brake cylinder compensating pressure chamber 24 and atmosphere;

Wh'en'the brakes of the carare releasedthe spring 5ii 'acting on: diaphragm 32'insuresthat the releasevalve 53F'will remainopen to dissipate to atmosphere any leakage of" fluid which may oceuzypast thesupply valve 59, to'thereby-insure against such pressure becoming effective in the compensatingv pressure chamber 24' of the brake cylinder device when notdesiredlflnd whichimight interfere with y a; subsequent application or brakes. Moreover,.. with. the brakes releasedthe spr n 511. positively maintains v the beam 41' in" contact withthe roller 64.. andithani ot. diaphragm 3|. in

crmitactzwith the casing. asshownz on. the-drawing;

to;- &Y0idi= rattle and needless; wear or. these and thesintersconnecting:parts;

Whenthecar; isrsetout on a siding for loadingr on for. unloading:v reloading. the: brake pipe "2 will be open to atmosphere: andthet brakezcy-le inder devices 6 willbe operatedto' appLy-theabitakes omthe 02min the same manner as above described and ,0: a; deg-rec; corresponding, to; the empty; or loaded condition thereof. Whenthe carrismgain picked-zupand placed in a trainthecompensating valve device 8: will: again operatein: response to charging: of: the brake-pipe 2 to adjust. or-readziust if: necessary; the position of: the fulcrum; roller. Mairnaccordance theenrpty oir loaded cone diti-on of the: car in the same; manner as herein beiiore described; whereby duringoperat'iomofithe can in the train theidegree of braking-:ofthe can williagainibezlimitedin accordance with-the empty 3 unloaded condition thereof.

Summary IItgWili-DOW be; seen that jwe have; provided a relatively: simple variable load brake: equipment forfreight carswhich is automaticwand positive inaoperation towary thedegneeofi braking on. the car-em" accordance; with: theempty on loaded-con! ditionr-thereoi. The'equipment constituteamainiy theesubstitutiom, for theyusual single-pressure type on brakeicylinden device now employed om cars, ofz a: compensating brake cylinder-device; provid: ing; a second: controlling fluid pressure; which is varied-sin inverseproportion to the degree: oiiload carried: by the car to thereby'limit: the braking or the carrimsub-stantial proportion torthe': degree of;"saicl load, andz-t-he addition of: aalo-adzcompena sati'ng devicewhich is automatically; adjustable im accordance; with the empty or loaded: condiition; of: thercar' forgautomatically regulatingv this secondicontrolpressurein the brake cylinder deflvicez,

Having nowvdescribed t-heinvention; what; we claim; as new ands desire to secure by Letters Patent, is:

1. In: a: vehicle? variable load br akerlequipment, int combination, a brake, pipe, brakecontrolling; means operative upon a reduction implies-a sure. oflfluid in said, brake pipe: toreffectsan; ap

plicatiorr; of brakes onts-aid vehicle, adjustable mechanismforlimiting the degree? of: said-pap plication-.: in accordance with thedegree; of load carried; by; said vehicle, motor means operable by fluidunder. press-ure for adjusting'said mechae nism', latch; means for; holding said' mecha nism; inzan adjusted condition and adapted: to be render-ed?inefiective upon; supply.- of fluid under. pressure: to a control; chamber, a: slide valve; disp0sed--:ina: valve.- chamberopenr torsair brakepipe--. and. havingpa; cut-in; positionianda =cuteofirposition a. passages connecting-said con trohcham-bentoathe seat of; said'slidevalve, second and-rthird passages; connecting said; motor means to said. seat, said slidevalue-in said out-in; tion-3opening the, first named: passage and i said seeondpassagee directly tosaid-valve chamben and, lapping said third, passage; and :in. said: out off -position 'openinglsaid first and third-passages to atmosphere, choke -means for-restricting flow ofirfluid under pressure" fromsaid thirdpassage a Tcheck; valve-int said second passage for preventing flow of: fluid-under pressure,therethroughqin the direction to said motor means, meaneopera; tive, by. said; latch means, subsequent.. to being rendered. ineffective, to; open saidcheclev valve,

and means cnntrolled icy-pressure vof; fluidin said.

17 brake pipe operative upon an increase in pressure therein to a chosen degree to move said slide valve to said cut-off position and upon a reduction in brake pipe pressure to a chosen lower degree to move said slide valve to said cut-in position.

2. In a vehicle variable load brake equipment, in combination, a brake pipe, brake controlling means operative upon a reduction in pressure in said brake pipe to effect an application of brakes on said vehicle, adjustable mechanism for limiting the degree of said application in accordance with the degree of load carried by said vehicle, motor means operable by fluid under pressure for adjusting said mechanism, latch means for holding said mechanism in an adjusted condition and adapted to be rendered ineffective upon supply of fluid under pressure to a control chamber, a slide valve disposed in a valve chamber open to said brake pipe and having a cut-in position and a cut-off position, a passageconnecting said control chamber to the seat of said slide valve, second and third passages connecting said motor means to said seat, a timing reservoir open at all times to said second passage, said slide valve in said cut-in position opening the first named passage and said second passage directly to said valve chamber and lapping said third passage and in said cut-off position opening said first and third passages to atmosphere, choke means for restricting flow of fluid under pressure from said third passage, a check valve in said second passage for preventing flow of fluid under pressure therethrough in the direction to said motor means, means operative by said latch means subsequent to being rendered ineffective to open said check valve, choke means for restricting flow of fluid under pressure from said brake pipe to said valve chamber, and means controlled by pressure of fluid in said brake pipe operative upon an increase in pressure therein to a chosen degree to move said slide valve to said cut-off position and upon a reduction in brake pipe pressure to a chosen lower degree to move said slide valve to said cut-in position.

3. In a vehicle variable load brake equipment, in combination, a brake pipe, brake controlling means operative upon a reduction in pressure in, said brake pipe to effect an application of brakes on said vehicle, adjustable mechanism for limiting the degree of said application in accordance with the degree of load carried by said vehicle,

valve to said cut-in position, another movable abutmentof greater area than the first named abutment and subject to pressure of fluid in another chamber and opposing pressure of said spring means and operative upon supply of fluid under pressure to said other chamber to increase the pressure of said spring means against the first named abutment and upon release of fluid under pressure from said other chamber to reduce the pressure of said spring means on said first named abutment, and a passage providing a constantly open communication between said other chamber and said control chamber.

4. In a vehicle variable load brake equipment, in combination, a brake pipe, brake controlling means operative upon a reduction in pressure of fluid in said brake pipe to effect an application of brakes on said vehicle, adjustable mechanism for limiting the degree of said application in accordance with the degree of load carried by said vehicle, motor means operable by fluid under pressure for adjusting said mechanism, latch means for holding said mechanism in an adjusted condition and adapted to be rendered ineffective by fluid under pressure, a cut-off slide valve disposed in a chamber and having a cut-in position and a cut-off position, means opening said chamber to said brakepipe, a timing reservoir, a check valve chamber, a check valve in said check valve chamber for closing a communication therebetween and said motor means, a passage perinanently connecting said chambers to each other and to the seat of said slide valve, said slide valve comprising means effective in the cut-in position motor means operable by fluid under pressure,

for adjusting said mechanism, latch means for holding said mechanism in an adjusted condition and adapted to be rendered ineffective upon supply of fluid under pressure to a control chamber, a cut-off valve having a cut-in position forest-ablishing communication between said brake pipe, and said motor means and control chamber for supplying fluid under pressure thereto, and having a cut-off position for releasing fluid under pressure from said control chamber and motor means, means for delaying release of fluid under pressure from said motor means with respect to release of fluid under pressure fromsaid control chamber, a spring, a movable abutment connected to said cut-off valve subject to opposing pressures of said spring and of fluid in said brake pipe, said abutment being operative upon an increase in brake pipe pressure to a degree to overcome said spring to move said cut-off valve to said cut-off position and upon a reduction in brake pipe pressure to a degree below thereof to open said passage to said valve chamber and to also establish communication between said valve chamber and latch means for supplying fluid under pressure thereto, and further comprising means effective in said cut-off position for opening said passage directly to said motor means and to atmosphere and for also opening said latch means to atmosphere, choke means in the atmospheric connection to said passage, means operative by said latch means, subsequent to becoming ineffective, to open said check valve, and

means operative upon an increase in pressure in said brake pipe to a chosen degree to move said cut-off slide valve to said cut-off position and upon a reduction in brake pipe pressure to a chosen lower degree to move said cut-off slidevalve to said cut-in position,

5 In a vehicle variable load brake equipment, in combination, a brake pipe, brake controlling means operative upon a reduction in pressure of fluid in said brake pipe to effect an application of brakes on said vehicle, adjustable mechanism for limiting the degree of said application in accordance with the degree of load carried by said vehicle, motor means operable upon supply of fluid under pressure to a chamber for adjusting said mechanism, latch means for latching said mechanism in an adjusted position and operable upon supply of fluid under pressure to a control chamber to release said mechanism for adjustment by said motor means, a timing reservoir, a check valve chamber, a passage connecting said reservoir and check valve chamber, a check valve in said check valve chamber for preventing flow of fluid under pressure through a communication from said passage to said motor means, means operable by said latch means, subsequent to releasing said mechanism, to open said check valve, a cut-off slide valve contained in a slide valve chamber and having a cut-in the pressure of said spring to move said cut-out position and a cut-off position, means opening irigsaid slide valveilch'a rnb'e t piston chamber, meahsfiol; 1i

eiejs lide va yeeehamleeil z a e ia iq 01 to, oyeroome said spsipg said spring beipg opega lve to moye ssaid lslideltvalye to sa id cutin Pr ent? i fluid: Q ll en e et degree, a second movab abutment of larger, area, methane first named} hutm ntg pe ble m supply of fluidunder lpressm e to a 'chambexf tq; increase the DIGSS QFB Of said;sp r'irl iggio a the first am a le v butm t e ei'fi ere le 1 9- 1 venting of fipidur lder; press g re from the last, amed Chamber ,to redgce t ejj yessure r, aid. spring on said first namedj movable algutrgrlent, and he assa e c nec in t e' e t n med wane?- bar and saidjconti ol' chamber. I r

n ve ioc ev ri ble ead. akeie uipmentg in combination, a brake pipe; brake copttollingf means including a rcom'pen slating device 013813121? 1111011 t n xtake i ed reesure t ef ect an, ap ic on r ;.es;0n.a h .1e t a e ree corresponding to the loaded qondition the eofg said c m sat dev ce qmpr n s n e al e, m eam, PQadjustabE$1 1 mL a Q. .b eYin aimk d p' ition; nd attem ts! qe t on. e firom v e e v u w ofidx 9 .2n. ra e upon sup l fzflu q; 1 1 P es ure to a bias p on amber t9; m ye ifiulcrum. to its pt sit e n r iu tin etez i r t reah e s id i spis qe mw blesup ns supply of fluid under pressure-'tqap adjusting V. a 'n ..t e xt n off movement'of; said a stipgj pis' ton by fluig r. piessuieto a s tipn: o res qedine i h.- the degree of loadopithe eh iole 'n'ieans opera: ble by saidadjusting tp iston u-goyr vemept thereof by fluid under faressui'et'o Tn'oyesaidfuk crime against pressure of fluid on saidbias piston in the direction of said ful l loadpositi'onto a position corresponding to thatpf 'saidadjusting" piston, means for suppiyin'g fluidunder pressure" to and for releasing fiui d under; pr essulfejfi om said bias and adjustin -pistonsin' unison,- and means for holding said fulcruin'in anadjxisted poslitio'n upon release of fluid'under pressure from Pe it n ponl a' reductio said iis to ns.

'7. In a vehicle variable load brake'equ ipmergg in combination, abralge pipe, brake controlling means including a compensating device operable upon a reduction in brak pipe pr'essure to eff-eet" an application of brakes on a vehicleto a degree corresponding to the loaded eonditionj thereof, said compensating device" comprising "an equal izipg beam, an adjiistable fulerum folisaidfbeam' haviri g a full-load position and art emptyja o sition ace m. id; 1111, 0m qsi m fl s 21 qnspp m le. onssupn jpt flui nqe s res'sur we bias, p s onc amb rt .mo e aid, itsemptx p si i an ad ustin pistonpi greater, ea than s i sspii tqn mey h c pen upplx,.,

ables pis qe. I

f lcrum toe nde DJQ SS Z'Qe Q meyel aidr ulerum agains reure fL ai 1a pi ton.;tq. 1ah.p:os -.si on4 nre pond negtee ha QD Q1; :F. Z1I ae ii stabl connec t e is oman oad: n; s i ,veh el e nden ess re q r .o mmf-sa and as shin .nston ieomw means otholdinges dfu mmm ill dosifii a n Ptessgrefl omsaid -p' tons; 1; -sne ehiszley ,b t oadr rek ee nipmen e; mb at qni; a rake i ee na k ro -tm lin; means s-ineluding v ensating deyiee opex able upon; a reductiont 1n rake pipe pxpessure to ffect, ke s on a vehicle to: a degree;-

dition; thereob said an application-ofibra zq rresp n vto thea 0 x1 om en tme devic ea an a iust le ing a, full-load positio spaced. from said.lfu11.,1

erum for; said beamhaw-e wand,- ane mpt e Po io bad'position, a biaspistonopenable upog supply f-Lfl d ulgden pgessure to *"a :bias .piston chambegz q- -mqye 'said ful crum' tas-e ty position; an adiil in neo re reatha d-b as: tonlmpvbl u n sup ly of fl uid under press to an iadje-usting p istbm ae hamb e n efdr' lm iillg thee entoi igs/e an cl u m jg istpns meansj,

n aw hiq eg've iablel eds akeeqmpment; v In o qmb nations flh eleupipe. make pentrou ng, mee m t ret ve 129 a r dl g p nfpressu e o Z ismV Qr'l mitine hegde e y e V- l-madame hs hedega e floed came y.

a d i hie 'e; m te m ws o b bygfiuid .un-Q

den m su sfora ystm sai me sm latch e .-f9rho p sai mec nism men, ad ust-7T1 d pp vn Qr een r.a Ju in saidltch mearis a mqyabl V butment-subj-ectgtoppposing pressures of said spring;means; and i of flui d' i rf a control-chamber and operativeufion; ari i hif stiv mltri i; %1Ye,! 1 %nm a1lm,fi; .c' tein. pee tiqnje ees abl nieg ommunieatiops e we nw a r e p p a tseislw pt IQQQQ Q QQQQIL-H there tbyflfl d-s u er umw nst releasing fluid under pressure from said motor means and control chamber, said cut-off means comprising a movable abutment subject on one side to pressure of fluid in said brake pipe, and a control spring, opposing pressure of fluid on said movable abutment of said cut-out means with a force less than the force of said spring means on said movable abutment of said latch means, said cut-off means being operative to said cut-off position upon an increase in brake pipe pressure sufficient to overcome said control spring and to said cut-in position upon a reduction in brake pipe pressure to a degree to render said control spring preponderant over brake pipe pressure.

10. In a variable load brake squipment for a vehicle having a sprung part and an unsprung part, a brake pipe, a brake cylinder device comprising a casing and a piston therein dividing said casing into a main pressure chamber at one side of said piston from a compensating chamber at the opposite sideand operative to pro:

vide a braking force on said vehicle equal to the difference in effect of fluid pressure in said chambers on said piston, brake controlling means operative upon a reduction in brake pipe pressure to supply fluid under pressure to said main chamber and upon an increase in pressure in said brake pipe to release fluid under pressure from said main chamber, a compensating device comprising an adjustable fulcrum and an. equalizing beam supported and operative on said fulcrum and subject opposingly to pressures of fluid in said chambers for varying the pressure of fluid in said compensating chamber in accordance with the adjustment of said fulcrum and the pressure of fluid in same main chamber, and adjusting means operable in accordance with the position of said sprung part with respect to said unsprung part to correspondingly adjust said ful crum relative to said lever.

11. In a variable load brake equipment for a vehicle having a sprung part and an unsprung part, a brake pipe, a brake cylinder device comprising a casing and a piston therein dividing said casing into a main pressure chamber at one side of said piston and a compensating chamber at the opposite side and operative to provide braking force on said vehicle equal to the difference in effect of fluid pressures in said chambers on said piston, brake controlling means operative upon a reduction in brake pipe pressure to supply fluid under pressure to said main chamber and upon an increase in pressure in said brake pipe to release fluid under pressure from said main chamber, a compensating device comprising a fulcrum member adjustable to empty and load positions and to positions therebetween, and means controlled by pressure of fluid in said main chamber cooperable with said fulcrum member to vary the pressure of fluid in said compensating chamber according to the position of said fulcrum member, adjusting means operable in accordance with the position of said sprung part with respect to said unsprung part to correspondingly adjust said fulcrum member in the direction of said load position, and means biasing said fulcrum member in the direction of said empty position against force of said adjusting means.

12. In a variable load brake equipment for a vehicle having a sprung part and an unsprung part, a brake pipe, a brake cylinder device comprising a casing and a piston therein dividing said casing into a main pressure chamber at one side means controlled by pressure of fluid in said main chamber cooperable with said fulcrum member to vary the pressure of fluid in said compensating chamber according to the position of said fulcrum member, adjusting means comprising a piston operable by fluid under pressure, and means operable by said piston in accordance with the position of said sprung part with respect to said unsprung part to correspondingly adjust said fulcrum member in the direction of said load position, and means for opposing adjustment of said fulcrum member by said piston with a force less than developed by said piston for biasing said fulcrum member to its said empty position.

13. In'a variable load brake equipment for a vehicle having a sprung part and an unsprung part, a brake pipe, a brake cylinder device comprising a casing and a piston therein divinding said casing into a main pressure chamber at one side of said piston and a compensating chamber at the opposite side and operative to provide braking force on said vehicle equal to the diiference in effect of fluid pressures in said chambers on said piston, brake controlling means operative upon a reduction in brake pipe pressure to supply fluid under pressure to said main chamber and upon an increase in pressure in said brake pipe to release fluid under pressure from said main chamber, a compensating device comprising a fulcrum member adjustable to empty and load positions and to positions therebetween, and means controlled by pressure of fluid in said main chamber cooperable with said fulcrum member to vary the pressure of fluid in said compensating chamber accordin 'to the position of said fulcrum member, adjusting means comprising 7 .ing means for holding said fulcrum member in an adjusted position, actuating means for rendering said locking means effective and ineffective, means for controlling said actuating means operative upon rendering said lockingmeans ineffective to effect a supply of fluid under pressure to actuate said piston means, means operative upon operation of said actuating means to render said locking means eifective to release fluid under pressure from said piston means, and means for retarding the release of fluid under pressure from said piston means.

14. In a variable load brake equipment for a vehicle having a sprung part and an unsprung part, a brake pipe, a brake cylinder device comprising a casing and a piston therein dividing said 253 ing member in accordance with the load on said. vehicle, a movable pilot abutment connected to one end of said member subject to pressure of fluid in said main chamber, a movable balancing abutment connected to the opposite end of said equalizing member subject to pressure of fluid in said compensating chamber opposing pressure of fluid on said pilot abutment, a fluid pressure supply valve operable by said adjusting abutment when pressure of fluid on said pilot abutment over-balances that on said adjusting abutment to supply fluid under pressure to said compensating chamber, a fluid pressure release valve operable by movement of said adjusting abutment when pressure thereon over-balances that on said pilot abutment to release fluid under pressure 2.6 from said compensating chamber}, and spring means biasing said adjusting abutment against said pilot abutment.

EARLE S. COOK. GLENN T. McCLURE. JOHN W. RUSH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,367,598 Miller Jan. 16, 1945 2,390,049 Baldwin Dec. 4, 1945 

